For your child, a strong core means developing the muscles throughout his abdomen, back and pelvis. These same muscle groups also allow him to climb, balance and maintain good posture, according to the an article in a 2010 edition of "Technique," a USA Gymnastics publication. Even if your child isn't interested in nailing back flips or landing cartwheels, strong core muscles can prevent muscle strain and discomfort during daily activities, and improve his balance and coordination.

Fun Pulls

These activities can be done on low-level carpet or a gym floor, and might require adult assistance. Pull one end of an old, sturdy, blanket across the floor while your child sits on the other half. Even though she's holding the sides of the blanket as you pull, she'll have to tighten her core muscles to keep from falling off. Start off slowly and increase the speed gradually. Older children can lie face down on a flat, square scooter gripping one end of a rope while you stand several feet away holding the other end. Have her pull toward you using the rope, to maintain her position on the scooter she'll need to engage her core.

Team Activities

If you have a few children in the neighborhood of similar size you can recruit them to play a variety of core-strengthening games. Playing tug of war, even if it's just between two people, requires your child to tighten his abdomen, back and pelvis while pulling. Wheelbarrow walks, where your child "walks" on his hands while his partner holds his ankles, requires engaging abdominal and back muscles to help move his upper body forward.

Water Activities

Water activities are a way for your child to build her core strength while staying cool in summer. If she's a proficient swimmer, swimming in any body of water, even if it's just the doggy paddle, works her abdomen and back. For a younger child who loves splashing in the backyard, let her help carry a child-size bucket or watering can of water from the hose to the kiddie pool or splash station. Walking and pouring with a a weighted bucket requires stabilizing her upper and lower abdominal muscles and lower back.

Everyday Activities Modified

Picking up a small object off the ground while standing on one foot requires your child to stabilize his core muscles, according to the University of Sydney. Standing on one foot while performing tasks such as picking up the playroom or selecting clothing from the bottom dresser drawer are just two ways to encourage core strength. Even a toddler or young preschooler can reap the core-strengthening benefits of bending over on one foot by playing hopscotch and picking up the token after each toss.